Abstract : The objective of the program is the development of new thermoplastic and thermosetting resins from phosphonitrilic chloride trimer for high-temperature insulation. Reactions of bismethylol-o-carborane or its disodium salt with P3N3(OC6H5)4Cl2 (I) gave low-molecular weight polymers. o-Carborane was thermally isomerized to m-carborane for use in polymerizations with phosphonitrilic monomers. The preparation of I was carried out on a large scale to give monomer for preparation of P-O-P-linked polymer. Monomer I was reacted with several aromatic diols and the resulting polymers examined by thermogravimetric analysis. (Author)